what we cannot say is if tamerlan tsarnaev and this man, now deceased, effort met, but mr. tsarnaev's parents, his father, live there, and he was himself here only last year for at least a month according to witnesses there. there is apparently now the first connection, it seems, between the alleged boston bomber suspect and extremist groups here. for some reason, mr. tsarnaev posted a link to a video of this man on his youtube account. wolf. >> because you know, nick, there is deep concern among federal and state, local law enforcement that when this older brother who is now dead, when he spent more than six months in dagestan where you are right now, he was potentially, this is the theory they're working on, he was trained on how to build a bomb, how to deal with these kinds of explosive devices. and he was indoctrinated, if you will, to become an extremist. that's the concern that they're investigating. what are you hearing on the scene for us about what do we know, specifically, about what he did when he was in dagestan last year? >> reporter: very unclear. we know he c